Skin science article
Medik8 Daily Radiance Vitamin C Versus IMAGE skincare Vital C Hydrating Repair Cream
Medik8 Daily Radiance Vitamin C Versus IMAGE skincare Vital C Hydrating Repair Cream This brightening day moisturizer is formulated around Tetrahexyldecyl Ascorbate and Tocopheryl Acetate to brighten dull-looking skin and soften the look of wrinkles. This barr
Medik8 Daily Radiance Vitamin C Versus IMAGE skincare Vital C Hydrating Repair Cream
This brightening day moisturizer is formulated around Tetrahexyldecyl Ascorbate and Tocopheryl Acetate to brighten dull-looking skin and soften the look of wrinkles.
This barrier-repair night moisturizer is formulated around Aloe Barbadensis Leaf Juice and Tetrahexyldecyl Ascorbate to strengthen the skin barrier and hydrate skin.
What's inside
Key Ingredients
Benefits
Concerns
Ingredients Side-by-side
Water
Tetrahexyldecyl Ascorbate
Diethylamino Hydroxybenzoyl Hexyl Benzoate
Dibutyl Adipate
Dimethicone
Ethylhexyl Triazone
Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine
C12-15 Alkyl Benzoate
Dicaprylyl Carbonate
Cetearyl Alcohol
Glycerin
Coco-Glucoside
Phenoxyethanol
Acrylates/C10-30 Alkyl Acrylate Crosspolymer
Cetearyl Glucoside
Tocopheryl Acetate
Hydroxyacetophenone
Disodium EDTA
Benzoic Acid
Xanthan Gum
Citrus Grandis Peel Oil
Sodium Hydroxide
Dehydroacetic Acid
Sodium Hyaluronate
Citrus Limon Peel Oil
Citrus Aurantium Bergamia Fruit Oil
Pelargonium Graveolens Flower Oil
Ethylhexylglycerin
Limonene
Citronellol
Linalool
Geraniol
Citral
Water, Tetrahexyldecyl Ascorbate, Diethylamino Hydroxybenzoyl Hexyl Benzoate, Dibutyl Adipate, Dimethicone, Ethylhexyl Triazone, Bis-Ethylhexyloxyphenol Methoxyphenyl Triazine, C12-15 Alkyl Benzoate, Dicaprylyl Carbonate, Cetearyl Alcohol, Glycerin, Coco-Glucoside, Phenoxyethanol, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Cetearyl Glucoside, Tocopheryl Acetate, Hydroxyacetophenone, Disodium EDTA, Benzoic Acid, Xanthan Gum, Citrus Grandis Peel Oil, Sodium Hydroxide, Dehydroacetic Acid, Sodium Hyaluronate, Citrus Limon Peel Oil, Citrus Aurantium Bergamia Fruit Oil, Pelargonium Graveolens Flower Oil, Ethylhexylglycerin, Limonene, Citronellol, Linalool, Geraniol, Citral
Aloe Barbadensis Leaf Juice
Glyceryl Stearate
Isostearyl Neopentanoate
PEG-100 Stearate
Simmondsia Chinensis Seed Oil
Caprylic/Capric Triglyceride
Citrus Aurantium Dulcis Oil
Brassica Campestris/Aleurites Fordi Oil Copolymer
Cetyl Alcohol
Stearyl Alcohol
Cyclopentasiloxane
Tocopherol
Ceteth-10 Phosphate
Dicetyl Phosphate
Magnesium Ascorbyl Phosphate
Panthenol
Squalane
Caprylyl Glycol
Glycine Soja Sterols
Linoleic Acid
Phospholipids
Glucosamine Hcl
Hexylene Glycol
Magnesium Aluminum Silicate
PEG-8
Butylene Glycol
Phytic Acid
Pisum Sativum Extract
Allantoin
Retinyl Palmitate
Bambusa Vulgaris Leaf/Stem Extract
Citrus Nobilis Peel Oil
Yeast Polysaccharides
Dipotassium Glycyrrhizate
Ascorbyl Palmitate
Pyruvic Acid
Tremella Fuciformis Sporocarp Extract
Citric Acid
Ascorbic Acid
Vitis Vinifera Seed Extract
Aloe Barbadensis Leaf Juice, Water, Glycerin, Dimethicone, C12-15 Alkyl Benzoate, Glyceryl Stearate, Isostearyl Neopentanoate, PEG-100 Stearate, Simmondsia Chinensis Seed Oil, Caprylic/Capric Triglyceride, Cetearyl Alcohol, Citrus Aurantium Dulcis Oil, Limonene, Brassica Campestris/Aleurites Fordi Oil Copolymer, Cetyl Alcohol, Tetrahexyldecyl Ascorbate, Stearyl Alcohol, Phenoxyethanol, Cyclopentasiloxane, Tocopherol, Ceteth-10 Phosphate, Dicetyl Phosphate, Magnesium Ascorbyl Phosphate, Panthenol, Squalane, Caprylyl Glycol, Glycine Soja Sterols, Linoleic Acid, Phospholipids, Ethylhexylglycerin, Glucosamine Hcl, Hexylene Glycol, Xanthan Gum, Magnesium Aluminum Silicate, PEG-8, Butylene Glycol, Phytic Acid, Sodium Hydroxide, Pisum Sativum Extract, Allantoin, Retinyl Palmitate, Bambusa Vulgaris Leaf/Stem Extract, Citrus Nobilis Peel Oil, Yeast Polysaccharides, Dipotassium Glycyrrhizate, Disodium EDTA, Sodium Hyaluronate, Benzoic Acid, Ascorbyl Palmitate, Pyruvic Acid, Tremella Fuciformis Sporocarp Extract, Citric Acid, Ascorbic Acid, Vitis Vinifera Seed Extract
Alternatives
Ingredients Explained
These ingredients are found in both products.
Ingredients higher up in an ingredient list are typically present in a larger amount.
Benzoic Acid is an organic acid that shows up in cosmetics as a preservative. It helps keep a product from spoiling by holding back the growth of yeast, mold, and some bacteria.
This ingredient also functions as a fragrance ingredient that helps mask the unpleasant scent of other ingredients.
The way it works is worth understanding; benzoic acid works when the formula is acidic. It is able to sneak into a microbe's cell and mess up how it functions to stop it from growing in an acidic product.
However, the acid switches to an inactive form and stops working if a product isn't acidic enough (above ~5 pH). This is why you'll often see it in low pH products or teamed up with other preservatives to cover the gap.
Safety wise, it's one of the better studied preservatives out there.
The Cosmetic Ingredient Review Expert Panel has concluded this ingredient to be safe for use in cosmetic formulations at concentrations up to 5%.
A large international review found this ingredient had no effects on the human body and had low irritation potential.
Just so you know, real world use is usually much lower than the 5% ceiling (usually 1% of less).
The EU caps it at 2.5% in rinse-off products, 1.7% in oral care, and 0.5% in leave-on products.
One thing worth mentioning (it's nothing to worry about): some people get a little stinging or flushing where they apply it. This isn't a true allergy; it's a temporary and harmless reaction. This is the same kind of mild tingle you might notice from sorbic acid.
C12-15 Alkyl Benzoate is a lightweight emollient made by combinig benzoic acid with fatty alcohols that are 12-15 carbons long.
In cosmetics, it plays several roles:
The Cosmetic Review Expert Panel has concluded the alkyl benzoate group to be safe as used in cosmetics; it wasn't found to be a skin irritant and unlikely to be absorbed due to its low water solubility.
This report recorded almost 1000 reported uses with concentrations up to 59% in leave-on products but your cosmetics will typically use 0.5-15% depending on the product.
It's often called a "SPF booster": this is because it keeps UV filters properly dissolved and evenly distributed to support a sunscreen's performance. It doesn't actually raise SPF on its own.
Overall, this ingredient is well tolerated.
This ingredient is fungal acne safe because it is an ester of benzoic acid.
Think of this ingredient as two parts stuck together: an oily part and an acid part. Malassezia only gets a meal when it can snip off a fatty acid to eat. With C12-15 Alkyl Benzoate, the acid part is benzoic acid, which isn't a fatty acid and which the yeast can't use as food.
Benzoic acid is actually used as a preservative to stop yeast from growing.
The oily part is a blend of C12-15 fatty alcohols but fatty alcohols in this size range can support only a little Malassezia growth (mostly for one species of Malassezia as well).
In the ingredient, those alcohols stay locked inside the molecule. The yeast can only reach them by snipping the benzoate bond, and that type of bond is harder for it to cut than a normal fatty bond.
So not much gets released. And whatever does get snipped comes packaged with benzoic acid, which discourages yeast growth.
Cetearyl alcohol is a waxy mixture of two fatty alcohols: cetyl alcohol and stearyl alcohol. It is an emollient and emulsifier.
Despite having "alcohol" in its name, it has nothing to do with drying solvent alcohols; the FDA also allows "alcohol-free" products to contain fatty alcohols like this ingredient.
It plays several roles in a formula:
Typical use levels for this ingredient sit around 1-10% and the Cosmetic Ingredient Review Expert Panel has affirmed safety at concentrations up to 25% in leave-on products.
Multiple assessments have found it to be non-irritating and non-sensitizing to most people.
However, there have been some cases of allergic contact dermatitis in patients with chronically compromised skin barriers.
Cetearyl alcohol has a comedogenic rating of 2 and irritancy rating of 1. Both of these numbers come from the 1989 study that used rabbit ears; a "2" means mildly comedogenic and a "1" means low irritancy.
Here's the catch: rabbit skin is more sensitive than human skin and throws a lot of false positives. A 1996 reappraisal found that ingredients rated 1-2 in the rabbit ear tests are generally safe for humans.
Remember comedogenic ratings are unable to assess the entire formula of a product or how it will react on your skin. Just be sure to patch test if you are unsure about certain ingredients.
This ingredient is not fungal acne safe. Cetearyl alcohol is a fatty alcohol with chain lengths that fall within the range that Malassezia can metabolize.
A 2019 study has also observed Malassezia growth in the presence of this ingredient, confirming it to be not-fungal acne safe.
Dimethicone is a type of synthetic silicone created from natural materials such as quartz. It is also known as polydimethylsiloxane.
What it does:
Dimethicone comes in different viscosities:
Depending on the viscosity, dimethicone has different properties.
Ingredients lists don't always show which type is used, so we recommend reaching out to the brand if you have questions about the viscosity.
This ingredient is unlikely to cause irritation because it does not get absorbed into skin. However, people with silicone allergies should be careful about using this ingredient.
Note: Dimethicone may contribute to pilling. This is because it is not oil or water soluble, so pilling may occur when layered with products. When mixed with heavy oils in a formula, the outcome is also quite greasy.
Disodium EDTA is a chelating agent. It grabs onto and deactivates metal ions that sneak into your products from water, packaging, or air.
This ingredient mainly works behind the scenes and helps with:
On top of that, this ingredient can counteract the effects of hard water by binding to the minerals in it.
One thing worth knowing is that Disodium EDTA has been shown to be a mild penetration enhancer. It can help other ingredients absorb into skin more effectively which can be a double-edged sword (great for actives, but can also make the active too strong if you have sensitive skin).
Clinical patch testing showed no significant skin irritation at typical use concentrations and minimal dermal absorption.
You'll most likely see this ingredient near the end of an ingredient list. It's typically found in concentrations less than 1%.
Ethylhexylglycerin is created from glycerin. It is a multitasker ingredient that:
The CIR Expert Panel found minimal skin absorption or sensitization of any kind in a safety assessment. Though this ingredient is considered well-tolerated, a small number of cases of allergic dermatitis have been published since 2002. Just be sure to patch test if you are unsure.
Industry-reported use ranges from 8% in rinse-off products and 2% in leave-on formulations.
Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum.
Topically, glycerin does several things at once:
Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3.
Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin.
This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products.
Just know very high concentrations (>40%) can feel tacky in low humidity.
Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine.
Limonene is a fragrance that adds scent and taste to a formulation.
It's found in the peel oil of citrus fruits and other plants such as lavender and eucalyptus. The scent of limonene is generally described as "sweet citrus".
Limonene acts as an antioxidant, meaning it helps neutralize free radicals.
When exposed to air, oxidized limonene may sensitize the skin. Because of this, limonene is often avoided by people with sensitive skin.
The term 'fragrance' is not regulated in many countries. In many cases, it is up to the brand to define this term. For instance, many brands choose to label themselves as "fragrance-free" because they are not using synthetic fragrances. However, their products may still contain ingredients such as essential oils that are considered a fragrance.
Phenoxyethanol is one of the most widely used preservatives in skincare (and for good reason!).
It has a large spectrum of antimicrobial activity and especially effective bacteria, yeast, and mold while only having a weak effect on your skin's natural microbiome.
On a cellular level, it disrupts the cell membranes of microbes by poking holes that make the cell leak. This shuts down the chemical reactions the microbe needs to make energy so it can no longer survive.
Another perk of this ingredient is that it stays functional across a wide pH range (3-10).
You'll often see it paired with boosters like Ethylhexylglycerin; one study showed that a 1:9 ratio of Ethylhexylglycerin to Phenoxyethanol damages bacterial membranes as effectively as doubling the Phenoxyethanol concentration on its own.
Typical use concentrations range from 0.3-1% depending on the formula, and this ingredient is capped at 1% int the EU.
Safety-wise, the fear mongering does not hold up to the evidence. The EU's Scientific Committee on Consumer Safety and FDA consider it safe as a preservative at up to 1%, including for children of all ages.
Adverse systemic effects only showed up in animal studies at exposures roughly 200x higher than what people get from cosmetics. And despite its very widespread use, this ingredient is a rare sensitizer and allergic reactions are uncommon.
Sodium Hyaluronate is the salt form of hyaluronic acid. It is a long sugar chain that is naturally found in your skin, joints, and connective tissue that maintains hydration and elasticity.
In skincare, it works as a humectant. It pulls water from the environment and deeper layers of skin and binds it to the surface.
Interestingly, the size of the molecule affects its behavior:
Some clinical evidence links low molecular weight versions to improved wrinkle depth, elasticity, anti-inflammatory effects, and barrier repair.
Many serums use a blend of both weights so you can get surface hydration plus longer-lasting and deeper effects.
You'll typically see concentrations between 0.1-2% for this ingredient.
Sodium Hydroxide is also known as lye or caustic soda. It is used to adjust the pH of products; many ingredients require a specific pH to be effective.
In small amounts, sodium hydroxide is considered safe to use. However, large amounts may cause chemical burns due to its high alkaline.
Your skin has a natural pH and acid mantle. This acid mantle helps prevent harmful bacteria from breaking through. The acid mantle also helps keep your skin hydrated.
"Alkaline" refers to a high pH level. A low pH level would be considered acidic.
Tetrahexyldecyl Ascorbate (THD) is a stable and oil-soluble form of Vitamin C.
THD is special in that it has the ability to travel deeper into skin than traditional ascorbic acid while maintaining the same skin benefits (double win!).
Because it’s oil-soluble, THD dives deep into your skin’s fatty layers (think ceramides and cholesterol) to fight off the kind of free radicals that mess with your skin barrier. This makes it a great pair with water-based vitamin C (ascorbic acid) that mainly works on the surface.
Even at just 0.1%, THD is already showing great antioxidant activity. When used up to 2%, it helps keep your skin happy and calm, especially when it’s stressed from pollution or sun.
Want to fade dark spots or tackle hyperpigmentation? You’ll want 5% or more. Pairing it with brightening buddies like niacinamide or licorice root gives even better results. One study even used 30% THD with other brighteners and saw real results on stubborn discoloration, even in melasma-prone skin.
A note on THD: It’s has a slightly silky, oily texture and usually shows up colorless or pale yellow (though the exact shade can vary by supplier).
While you can sneak it into water-based formulas, it really shines when paired with silicones or oils, which help your skin soak it up better.
THD is pretty stable, but it’s still vulnerable to degradation like ascorbic acid. Too much light or heat (above 113°F / 45°C) can break it down over time. Go for dark and opaque packaging that keeps it safe and shady!
Read more about other types of Vitamin C:
Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product.
So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation.
You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated!
Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny.
On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multiple sugar molecules bonded together.
Xanthan gum is a pretty common and great ingredient. It is a natural, non-toxic, non-irritating ingredient that is also commonly used in food products.